Medium conveying apparatus to notify user of cleaning instruction or replacement instruction of feed roller

ABSTRACT

A medium conveying apparatus includes a storage device, a feed roller to feed a medium, and a processor to determine whether a conveyance abnormality of the medium fed by the feed roller has occurred, store in the storage device that the conveyance abnormality has occurred and stop feeding of the medium when the processor determines that the conveyance abnormality has occurred, and notify a user of a cleaning instruction or a replacement instruction of the feed roller based on an occurrence degree of the conveyance abnormality for a plurality of media fed by the feed roller.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority of prior Japanese Patent Application No. 2020-217176, filed on Dec. 25, 2020, the entire contents of which are incorporated herein by reference.

TECHNICAL FIELD

Embodiments discussed in the present specification relate to medium feeding.

BACKGROUND

A medium conveying apparatus, such as a scanner, feeds a medium using a feed roller. In such a medium conveying apparatus, when the feed roller is dirty or is worn away, a slip, a jam or a multi-feed, etc., of the medium may occur. When the slip, the jam or the multi-feed, etc., of the medium has occurred, the user is required to reset the medium to a medium tray and re-feed it.

An image forming apparatus which determines whether there is a sign of an occurrence of a paper feed jam based on an occurrence rate of a paper feed delay, and notifies a request for replacement of a paper feed rotating body when a start condition number of papers are fed after determining that there is the sign, or when a start condition period has elapsed after determining that there is the sign, is disclosed (Japanese Unexamined Patent Publication (Kokai) No. 2017-100864).

A feeding apparatus which prompts replacement or cleaning of a separating module when the number of times of which a time from when a feeding from the separating module starts to when the paper detecting module detects is more than a predetermined time, is equal to or more than a predetermined number of times, is disclosed (Japanese Unexamined Patent Publication (Kokai) No. 2008-222345).

SUMMARY

According to some embodiments, a medium conveying apparatus includes a storage device, a feed roller to feed a medium, and a processor to determine whether a conveyance abnormality of the medium fed by the feed roller has occurred, store in the storage device that the conveyance abnormality has occurred and stop feeding of the medium when the processor determines that the conveyance abnormality has occurred, and notify a user of a cleaning instruction or a replacement instruction of the feed roller based on an occurrence degree of the conveyance abnormality for a plurality of media fed by the feed roller.

According to some embodiments, a method for notifying a user, includes, feeding a medium by a feed roller, determining whether a conveyance abnormality of the medium fed by the feed roller has occurred, storing in a storage device that the conveyance abnormality has occurred and stopping feeding of the medium when it is determined that the conveyance abnormality has occurred, and notifying a user of a cleaning instruction or a replacement instruction of the feed roller based on an occurrence degree of the conveyance abnormality for a plurality of media fed by the feed roller.

According to some embodiments, a computer-readable, non-transitory medium stores a computer program. The computer program causes a medium conveying apparatus including a storage device and a feed roller to feed a medium, to execute a process including determining whether a conveyance abnormality of the medium fed by the feed roller has occurred, storing in the storage device that the conveyance abnormality has occurred and stopping feeding of the medium when it is determined that the conveyance abnormality has occurred, and notifying a user of a cleaning instruction or a replacement instruction of the feed roller based on an occurrence degree of the conveyance abnormality for a plurality of media fed by the feed roller.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view illustrating a medium conveying apparatus 100.

FIG. 2 is a diagram for illustrating a conveyance path inside the medium conveying apparatus 100.

FIG. 3 is a block diagram illustrating a schematic configuration of the medium conveying apparatus 100.

FIG. 4 is a diagram illustrating schematic configurations of a storage device 140 and a processing circuit 150.

FIG. 5 is a flowchart illustrating an operation example of a medium reading processing.

FIG. 6 is a graph for illustrating a slip rate.

FIG. 7 is a graph for illustrating the moving average value of the slip rate.

FIG. 8 is a flowchart illustrating an operation example of a notification processing.

FIG. 9 is a graph for illustrating cleaning of a feed roller 113.

FIG. 10 is a graph illustrating an example of a transition of a moving average value of the slip rate.

FIG. 11 is a diagram for illustrating a conveyance path inside another medium conveying apparatus 200.

FIG. 12 is a diagram illustrating a schematic configuration of a processing circuit 350 according to another embodiment.

DESCRIPTION OF EMBODIMENTS

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory, and are not restrictive of the invention, as claimed.

Hereinafter, a medium conveying apparatus, a method for notifying a user, and a computer-readable, non-transitory medium storing a computer program according to an embodiment, will be described with reference to the drawings. However, it should be noted that the technical scope of the invention is not limited to these embodiments, and extends to the inventions described in the claims and their equivalents.

FIG. 1 is a perspective view illustrating a medium conveying apparatus 100 configured as an image scanner. The medium conveying apparatus 100 conveys and images a medium being a document. The medium is a paper, a thick paper, a card, etc. The paper includes a plurality of types of paper, such as art paper, coated paper, matte coated paper, fine paper, medium paper, etc. The medium conveying apparatus 100 may be a fax machine, a copying machine, a multifunctional peripheral (MFP), etc. A conveyed medium may not be a document but may be an object being printed on etc., and the medium conveying apparatus 100 may be a printer etc.

The media conveying device 100 includes a first housing 101, a second housing 102, a medium tray 103, the ejection tray 104, an operation device 105 and a display device 106, etc.

The first housing 101 is located on an upper side of the medium conveying apparatus 100 and is engaged with the second housing 102 by hinges so as to be opened and closed at a time of medium jam, during cleaning the inside of the medium conveying apparatus 100, etc.

The medium tray 103 is engaged with the second housing 102 in such a way as to be able to place a medium to be conveyed. The medium tray 103 is provided on a side surface of the second housing 102 on a medium supply side to be movable in a substantially vertical direction (height direction) A1. The ejection tray 104 is a tray formed on the first housing 101 capable of holding the ejected medium, to load the ejected medium.

The operation device 105 includes an input device such as a button, and an interface circuit acquiring a signal from the input device, receives an input operation by a user, and outputs an operation signal based on the input operation by the user. The display device 106 includes a display including a liquid crystal or organic electro-luminescence (EL), and an interface circuit for outputting image data to the display, and displays the image data on the display.

In FIG. 1, an arrow A2 indicates a medium conveying direction, and an arrow A3 indicates a width direction perpendicular to the medium conveying direction. Hereinafter, an upstream refers to an upstream in the medium conveying direction A2, and a downstream refers to a downstream in the medium conveying direction A2.

FIG. 2 is a diagram for illustrating a conveyance path inside the medium conveying apparatus 100.

The conveyance path inside the medium conveying apparatus 100 includes a first medium sensor 111, a pick roller 112, a feed roller 113, a brake roller 114, an encoder 115, a second medium sensor 116, an ultrasonic transmitter 117 a, an ultrasonic receiver 117 b, first to eighth conveying rollers 118 a to 118 h, first to eighth driven rollers 119 a to 119 h, a first imaging device 120 a and a second imaging device 120 b, etc.

The number of each of the pick roller 112, the feed roller 113, the brake roller 114, the first to eighth conveying rollers 118 a to 118 h, and/or the first to eighth driven rollers 119 a to 119 h is not limited to one, and may be a plurality. In that cases, a plurality of feed rollers 113, brake rollers 114, first to eighth conveying rollers 118 a to 118 h and/or first to eighth driven rollers 119 a to 119 h are located apart from each other along in the wide direction A3. Hereinafter, the first imaging device 120 a and the second imaging device 120 b may be collectively referred to as imaging devices 120.

The surface of the first housing 101 facing the second housing 102 forms a first guide 101 a of the medium conveyance path, and the surface of the second housing 102 facing the first housing 101 forms a second guide 102 a of the medium conveyance path.

The first medium sensor 111 is located on the medium tray 103, i.e., on the upstream side of the feed roller 113 and the brake roller 114, to detect a placing state of the medium in the medium tray 103. The first medium sensor 111 determines whether or not the medium is placed on the medium tray 103, by a contact detection sensor in which a predetermined current flows when a medium is in contact or a medium is not in contact. The first medium sensor 111 generates and outputs a medium detection signal changing the signal value between a state in which a medium is placed on the medium tray 103 and a state in which a medium is not placed. The first medium sensor 111 is not limited to the contact detection sensor, and any other sensor, such as a light detection sensor, capable of detecting the presence or absence of the medium may be used as the first sensor 111.

The pick roller 112 is provided in the first housing 101, and comes into contact with the medium placed on the medium tray 103 lifted to a height substantially equal to that of the medium conveyance path to feed the medium to the downstream side.

The feed roller 113 is located in the first housing 101, and on the downstream side of the pick roller 112, to feed the medium placed on the medium tray 103 and fed by the pick roller 112 toward further the downstream side. The brake roller 114 is located in the second housing 102 to face the feed roller 113. The feed roller 113 and the brake roller 114 perform a medium separation operation to separate the media and feed them one by one. The feed roller 113 is located on the upper side with respect to the brake roller 114, the medium conveying apparatus 100 feeds the medium by a so-called top-first type. A brake pad may be used instead of the brake roller 114.

The encoder 115 is an example of a sensor to detect a movement distance of the medium fed by the feed roller 113. The encoder 115 is located on the downstream side of the feed roller 113 and the brake roller 114 and on the upstream side of the first conveying roller 118 a and the first driven roller 119 a in the medium conveying direction A2, in particular, in the vicinity of the feed roller 113. The encoder 115 includes a disk on which a large number of slits (light transmission holes) are formed, the disk being provided to rotate according to a medium fed by the feed roller 113, and a light emitter and a light receiver provided to face one another with the disk in between. The light emitter is an LED (Light Emitting Diode), etc., and emits light toward the disk (light receiver). The light receiver receives the light emitted by the light emitter through the disk. The light receiver detects the number of times of changes from a state in which a slit exists between the light emitter and the light receiver to a state in which the slit is not present and the light is blocked by the disk, within a predetermined period. The light receiver detects a movement distance of the medium fed by the feed roller 113 by multiplying the detected number of times of changes by a distance by which an outer peripheral surface of the encoder 115 moves when the disk rotates by a distance between two slits adjacent to each other. The encoder 115 generates and outputs a distance signal indicating the detected movement distance.

The second medium sensor 116 is located on the downstream side of the feed roller 113 and the brake roller 114 and on the upstream side of the first conveying roller 118 a and the first driven roller 119 a in the medium conveying direction A2. The second medium sensor 116 includes a light emitter and a light receiver provided on one side with respect to the conveyance path of the medium, and a reflection member such as a mirror provided at a position facing the light emitter and the light receiver with the conveyance path in between. The light emitter is an LED, etc., and emits light toward the medium conveyance path. On the other hand, the light receiver receives light projected by the light emitter and reflected by the reflection member, and generates and outputs a second medium signal being an electric signal based on intensity of the received light.

When a medium exists at a position of the second medium sensor 116, light projected by the light emitter is shaded by the medium. Therefore, a signal value of the second medium signal is changed in a state in which the medium exists at the position of the second medium sensor 116 and a stated in which a medium does not exist at the position. Thus, the second medium sensor 116 detects whether or not the medium exists at the position, to detect the fed medium. The light emitter and the light receiver of the second medium sensor 116 may be provided at positions facing one another with the conveyance path in between, and the reflection member may be omitted. The second medium sensor 116 may detect the presence of the medium by a contact detection sensor, etc., in which a predetermined current flows when a medium is in contact or a medium is not in contact.

The ultrasonic transmitter 117 a and the ultrasonic receiver 117 b are located on the downstream side of the feed roller 113 and the brake roller 114 and on the upstream side of the first conveying roller 118 a and the first driven roller 119 a in the medium conveying direction A2. The ultrasonic transmitter 117 a and the ultrasonic receiver 117 b are located close to the conveyance path of a medium in such a way as to face one another with the conveyance path in between. The ultrasonic transmitter 117 a outputs an ultrasonic wave. On the other hand, the ultrasonic receiver 117 b receives the ultrasonic wave output from the ultrasonic transmitter 117 a and passing through the fed medium, and generates and outputs an ultrasonic wave signal being an electric signal corresponding to the received ultrasonic wave. Hereinafter, the ultrasonic transmitter 117 a and the ultrasonic receiver 117 b may be collectively referred to as an ultrasonic sensor 117.

The first to eighth conveying rollers 118 a to 118 h and the first to eighth driven rollers 119 a to 119 h are provided on the downstream side of the feed roller 113 and the brake roller 114, to convey the medium fed by the feed roller 113 and the brake roller 114 toward the downstream side.

The first imaging device 120 a includes a line sensor based on a unity-magnification optical system type contact image sensor (CIS) including an imaging element based on a complementary metal oxide semiconductor (CMOS) linearly located in a main scanning direction. Further, the first imaging device 120 a includes a lens for forming an image on the imaging element, and an A/D converter for amplifying and analog-digital (A/D) converting an electric signal output from the imaging element. The first image pickup device 120 a generates and outputs an input image by imaging a front side of the conveyed medium.

Similarly, the second imaging device 120 b includes a line sensor based on a unity-magnification optical system type CIS including an imaging element based on a CMOS linearly located in a main scanning direction. Further, the second imaging device 120 b includes a lens for forming an image on the image element, and an A/D converter for amplifying and analog-digital (A/D) converting an electric signal output from the imaging element. The second imaging device 120 b generates and outputs an input image by imaging a back side of the conveyed medium.

Only either of the first imaging device 120 a and the second imaging device 120 b may be located in the medium conveying apparatus 100 and only one side of a medium may be read. Further, a line sensor based on a unity-magnification optical system type CIS including an imaging element based on charge coupled devices (CCDs) may be used in place of the line sensor based on a unity-magnification optical system type CIS including an imaging element based on a CMOS. Further, a line sensor based on a reduction optical system type line sensor including an imaging element based on CMOS or CCDs.

A medium placed on the medium tray 103 is conveyed in the medium conveying direction A2 between the first guide 101 a and the second guide 102 a by the pick roller 112 rotating in a medium feeding direction A11 and the feed roller 113 rotating in a medium feeding direction A12. On the other hand, when a plurality of media are placed on the medium tray 103, only a medium in contact with the feed roller 113, out of the media placed on the medium tray 103 is separated, by the brake roller 114 rotating in a direction A13 opposite to the medium feeding direction.

The medium is fed to an imaging position of the imaging device 120 while being guided by the first guide 101 a and the second guide 102 a, by the first to second conveyance rollers 118 a to 118 b rotating in directions of arrows A14 to A15, respectively, and is imaged by the imaging device 120. The medium is ejected on the ejection tray 104 by the third to eighth conveyance rollers 118 c to 118 h rotating in directions of arrows A16 to A21, respectively.

FIG. 3 is a block diagram illustrating a schematic configuration of the medium conveying apparatus 100.

The medium conveying apparatus 100 further includes a motor 131, an interface device 132, a storage device 140, and a processing circuit 150, etc., in addition to the configuration described above.

The motor 131 includes one or more motors, and rotatably drives the pick roller 112, the feed roller 113, the brake roller 114, and the first to eighth conveying rollers 118 a to 118 h by a control signal from the processing circuit 150 to feed and convey the medium. The first to eighth driven rollers 119 a to 119 h may be provided to rotate by the driving force from the motor 131 rather than to be driven to rotate according to the rotation of the first to eighth conveying rollers 118 a to 118 h.

The interface device 132 includes, for example, an interface circuit conforming to a serial bus such as universal serial bus (USB), is electrically connected to an unillustrated information processing device (for example, a personal computer or a mobile information terminal), and transmits and receives an input image and various types of information. Further, a communication device including an antenna transmitting and receiving wireless signals, and a wireless communication interface circuit for transmitting and receiving signals through a wireless communication line in conformance with a predetermined communication protocol may be used in place of the interface device 132. For example, the predetermined communication protocol is a wireless local area network (LAN).

The storage device 140 is an example of a storage module. The storage device 140 includes a memory device such as a random access memory (RAM) or a read only memory (ROM), a fixed disk device such as a hard disk, or a portable storage device such as a flexible disk or an optical disk. Further, the storage device 140 stores a computer program, a database, a table, etc., used for various types of processing in the medium conveying apparatus 100. The computer program may be installed on the storage device 140 from a computer-readable, non-transitory medium such as a compact disc read only memory (CD-ROM), a digital versatile disc read only memory (DVD-ROM), etc., by using a well-known setup program, etc.

The processing circuit 150 operates in accordance with a program previously stored in the storage device 140. The processing circuit 150 is, for example, a CPU (Central Processing Unit). The processing circuit 150 may be a digital signal processor (DSP), a large scale integration (LSI), an application specific integrated circuit (ASIC), a field-programmable gate array (FPGA), etc.

The processing circuit 150 is connected to the operation device 105, the display device 106, the first medium sensor 111, the encoder 115, the second medium sensor 116, the ultrasonic sensor 117, the imaging device 120, the motor 131, the interface device 132 and the storage device 140, etc., and controls each of these units. The processing circuit 150 controls the motor 131 to feed and convey the medium, and controls the imaging device 120 to acquire an input image, and transmits the acquired input image to the information processing apparatus via the interface device 132. Further, the processing circuit 150 determines whether or not a conveyance abnormality of the fed medium has occurred, and notifies the user of a warning based on an occurrence degree of the conveyance abnormality.

FIG. 4 is a diagram illustrating schematic configurations of a storage device 140 and a processing circuit 150.

As shown in FIG. 4, each program such as a control program 141, a calculation program 142, a determination program 143 and a notification program 144, etc., is stored in the storage device 140. Each of these programs is a functional module implemented by software operating on a processor. The processing circuit 150 reads each program stored in the storage device 140 and operates in accordance with each read program. The processing circuit 150 functions as a control module 151, a calculation module 152, a determination module 153 and a notification module 154.

FIG. 5 is a flowchart illustrating an operation example of a medium reading processing.

Referring to the flowchart illustrated in FIG. 5, an operation example of the medium reading processing in the medium conveying apparatus 100 will be described below. The operation flow described below is executed mainly by the processing circuit 150 in cooperation with each element in the medium conveying apparatus 100, in accordance with a program previously stored in the storage device 140.

First, the control module 151 stands by until an instruction to read a medium is input by the user by use of the operation device 105 or the information processing device, and an operation signal instructing to read the medium is received from the operation device 105 or the interface device 132 (step S101).

Next, the control module 151 acquires the first medium signal from the first medium sensor 111, and determines whether or not a medium is placed on the medium tray 103, based on the acquired first medium signal (step S102). When a medium is not placed on the medium tray 103, the control module 151 returns the processing to step S101 and stands by until newly receiving an operation signal from the operation device 105 or the interface device 132.

On the other hand, when the medium is placed on the medium tray 103, the control module 151 drives the motor 131 and rotates the pick roller 112, the feed roller 113, the brake roller 114, and the first to eighth conveying rollers 118 a to 121 h (step S103). Thus, the control module 151 feeds and conveys the medium placed on the medium tray 103.

Next, the calculation module 152 calculates the slip rate between the feed roller 113 and the medium fed by the feed roller 113 based on the drive amount of the motor 131 and the movement distance of the medium fed by the feed roller 113 (step S104). The slip rate indicates a degree to which the medium did not move by slipping on an outer peripheral surface of the feed roller 113 even though the feed roller 113 is rotated.

The calculation module 152 monitors the drive amount by which the control module 151 drives the motor 131 to rotate the feed roller 113, and periodically acquires the distance signal from the encoder 115, while the drive amount is within a predetermined range. The predetermined range is set to, for example, a range corresponding to a period from when the medium passes through a position of the encoder 115 after the feeding of the medium is started to when the medium reaches a nip position between the first conveying roller 118 a and the first driven roller 119 a. The predetermined range is more preferably limited to a range corresponding to a period in which the encoder 115 is stably rotated by the medium.

The calculation module 152 calculates the movement distance of the outer peripheral surface of the feed roller 113, by multiplying the drive amount (the number of pulses) of the motor 131 in a period in which the distance signal is acquired from the encoder 115, and the movement distance of the outer peripheral surface of the feed roller 113 per pulse. Further, the calculation module 152 calculates the sum of the movement distance indicated in the distance signal acquired from the encoder 115 in that period, as the movement distance of the fed medium. The calculation module 152 calculates the slip rate according to the following equation (1) based on the movement distance of the outer peripheral surface of the feed roller 113 and the movement distance of the fed medium.

(the slip rate)=1−(the movement distance of the fed medium)/(the movement distance of the outer peripheral surface of the feed roller 113)  (1)

FIG. 6 is a graph for illustrating the slip rate.

The horizontal axes of graph 600, graph 610 and graph 620 of FIG. 6 indicate the drive amount of the motor 131, the vertical axes of graph 600, graph 610 and graph 620 indicate the slip rate. Graph 600 shows the slip rate when the feed roller 113 is normal. Graph 610 shows the slip rate when the surface of the feed roller 113 is dirty, i.e., when paper dust is adhered to the surface of the feed roller 113. Graph 620 shows the slip rate when the feed roller 113 is worn away, i.e., when the roller diameter is reduced in size and the grooves are reduced in size. As shown in the graph 600, the maximum value of the slip rate is less than 0.3 when the feed roller 113 is normal. On the other hand, as shown in the graph 610, the maximum value of the slip rate is equal to or more than 0.3, and is less than 0.4 when the surface of the feed roller 113 is dirty. Further, as shown in the graph 620, the maximum value of the slip rate is equal to or more than 0.6 when the feed roller 113 is worn away.

That is, the medium conveying apparatus 100 can accurately determine whether the feed roller 113 is normal, dirty, or worn away based on the slip rate.

The calculation module 152 assigns an identification number (medium ID) to the currently fed medium, and stores the calculated slip rate in association with the medium ID in the storage device 140. A numerical value, which is incremented each time the medium is fed and whose initial value is 1, i.e., a numerical value indicating what number the medium is fed since the start of use (after shipment) of the medium conveying apparatus 100, is assigned as the medium ID.

Next, the calculation module 152 calculates the moving average value of the slip rate in a predetermined number of media fed by the feed roller 113 (step S105). The calculation module 152 reads the slip rate calculated for the most recent predetermined number of media from the storage device 140, and calculates the average value of the read predetermined number of the slip rate.

FIG. 7 is a graph for illustrating the moving average value of the slip rate.

Graph 700 of FIG. 7 shows the slip rate when the feed roller 113 is worn away, and graph 710 of FIG. 7 shows the moving average value of the slip rate calculated for the most recent 50 media. The horizontal axis of graph 700 indicates the drive amount of the motor 131, the vertical axis of graph 700 indicates the slip rate. On the other hand, the horizontal axis of graph 710 indicates the drive amount of the motor 131, the vertical axis of graph 710 indicates the moving average value of the slip rate. As shown in graph 700, the slip rate varies greatly with the timing being measured when the feed roller 113 is worn away. On the other hand, as shown in graph 710, the moving average value of the slip rate is stable without varying greatly.

That is, the medium conveying apparatus 100 can more accurately determine whether or not the feed roller 113 is normal, dirty, or worn away based on the moving average value of the slip rate. The variation of the moving average value is too large when the number of data sampling for calculating the moving average value is 20 or less, conversely the variation of the moving average value is too small (the sensitivity is reduced) when the number of data sampling is 100 or more. Therefore, the number of data sampling is preferably larger than 20 and smaller than 100, and more preferably about 50.

Next, the notification module 154 determines whether or not the calculated moving average value is equal to or less than a slip threshold (step S106). The slip threshold is set in advance in consideration of the medium reading speed (processing speed) of the medium conveying apparatus 100, and is set to, for example, 0.25. When the moving average value is more than the slip threshold, the notification module 154 proceeds the process to step S108, without performing a particular process.

On the other hand, when the moving average value is equal to or less than the slip threshold, the notification module 154 sets a normal flag to ON (step S107). The normal flag is a flag indicating whether or not the slip rate indicates a normal value so far from when the conveyance abnormality of the medium last occurred. The normal flag is set to OFF at the start of use (at the time of shipment) of the medium conveying apparatus 100, or when the conveyance abnormality of the medium occurs. The normal flag may also be set to OFF when the apparatus is started. That is, the normal flag is set to ON when the moving average value calculated so far from when the conveyance abnormality of the medium last occurred is equal to or less than the slip threshold even once, and is set to OFF when the calculated moving average value is always larger than the slip threshold.

Incidentally, the normal flag may be set to ON when the moving average value calculated so far from when the conveyance abnormality of the medium last occurred is always equal to or less than the slip threshold, and be set to OFF when the calculated moving average value is larger than the slip threshold even once.

Next, the determination module 153 determines whether or not the front end of the medium has passed through the position of the second medium sensor 116 (step S108). The determination module 153 acquires the second medium signal periodically from the second medium sensor 116, and determines whether or not the medium exists at the position of the second medium sensor 116, based on the acquired second medium signal. When a signal value of the second medium signal changes from a value indicating that a medium does not exist to a value indicating that a medium exists, the determination module 153 determines that the front end of the medium has passed through the position of the second medium sensor 116.

When the front end of the medium has not yet passed through the position of the second medium sensor 116, the determination module 153 determines whether a predetermined time has elapsed since starting the feeding of the medium (step S109). The predetermined time is set in advance at a time considered to indicate that the conveyance abnormality such as the jam of the medium has occurred and the medium is not fed correctly. When the predetermined time has not yet elapsed since starting the feeding of the medium, the determination module 153 returns the process to the step S108 and repeats the processes of steps S108 to S109.

On the other hand, when the predetermined time has elapsed since starting the feeding of the medium, the determination module 153 determines that the conveyance abnormality such as the jam (paper jam) or the slip of the medium has occurred around the feed roller 113 and the brake roller 114 (step S110).

When the determination module 153 determines that the conveyance abnormality of the medium has occurred, the control module 151 stores in the storage device 140 that the conveyance abnormality of the medium has occurred. Further, the control module 151 stores the medium ID assigned to the medium fed currently in the storage device 140 as the medium ID of the medium on which the conveyance abnormality has occurred. Further, the control module 151 stops the motor 131 to stop the rotation of the pick roller 112, the feed roller 113, the brake roller 114, and the first to eighth conveying rollers 118 a to 118 h, and stop feeding and conveying of the medium (step S111).

Next, the notification module 154 executes a notification processing (step S112), and ends the series of steps. In the notification processing, the notification module 154 notifies the user of a cleaning instruction or a replacement instruction of the feed roller 113 based on an occurrence degree of the conveyance abnormality in fed media and the slip rate. Details of the notification processing will be described later.

On the other hand, in step S108, when the front end of the medium has passed through the position of the second medium sensor 116, the determination module 153 determines that the conveyance abnormality of the medium has not occurred around the feed roller 113 and the brake roller 114 (step S113). In this way, the determination module 153 determines whether or not the conveyance abnormality of the medium fed by the feed roller 113 has occurred. In particular, the determination module 153 determines whether or not the conveyance abnormality of the medium has occurred, based on a comparison between the time from the start of feeding the medium until the second medium sensor 116 detects the medium and a threshold (the predetermined time).

Next, the control module 151 causes the imaging device 120 to image the conveyed medium to acquire the input image, and outputs the acquired input image by transmitting it to the information processing apparatus via the interface device 132 (step S114). The control module 151 acquires the input image after a rear end of the medium has passed through the imaging position of the imaging device 120. The control module 151 determines that the rear end of the medium has passed through the imaging position of the imaging device 120 when the second predetermined time has elapsed since the start of feeding the medium. The control module 151 may determine whether or not the rear end of the medium has passed through the imaging position of the imaging device 120, based on a detection result of the medium by a medium sensor (not shown) located around the imaging device 120.

Next, the control module 151 determines whether or not a medium remains on the medium tray 103 based on the first medium signal received from the first medium sensor 111 (step S115). When a medium remains on the medium tray 103, the control module 151 returns the process to step S104 and repeats the processes in steps S104 to S115.

On the other hand, when a medium does not remain on the medium tray 103, the control module 151 stops the motor 131 to stop the rotation of the respective rollers (step S116), and ends the series of steps.

Incidentally, the process of step S105 may be omitted, and in step S106 to S107, the notification module 154 may set the normal flag to ON when the slip rate calculated for the medium fed presently is equal to or less than the slip threshold. In this case, in the notification processing to be described later, the notification module 154 notifies the user of the cleaning instruction or the replacement instruction of the feed roller 113 based on the slip rate. In this case, the medium conveying apparatus 100 can reduce the processing load of the medium reading processing, although there is a high possibility that the user is notified of the cleaning instruction or the replacement instruction of the feed roller 113 even though the feed roller 113 is not dirty or worn away.

Further, in steps S108 to S109, the determination module 153 may determine whether or not a conveyance abnormality of the medium has occurred, in addition to or in place of using the time until the medium passes through the position of the second medium sensor 116, using other methods.

For example, the medium conveying apparatus 100 determines whether or not the jam of the medium has occurred due to sound. In that case, the medium conveying apparatus 100 further includes a microphone, a filter, an amplifier and a sound A/D converter (not shown), etc. The microphone is located to fix to a frame inside the first housing 101 or the second housing 102, in the vicinity of the feed roller 113, in particular, on the downstream side of the feed roller 113 and the brake roller 114 and on the upstream side of the first conveying roller 118 a and the first driven roller 119 a. The microphone collects the sound generated by the medium during conveyance and outputs an analog sound signal according to an intensity of the collected sound. The filter applies a band-pass filter to pass a signal of a predetermined frequency band, to the analog sound signal output from the microphone, and outputs it to the amplifier. The amplifier amplifies the signal output from the filter and outputs it to the sound A/D converter. The sound A/D converter converts the analog sound signal output from the amplifier into a digital sound signal and outputs it to the processing circuit 150.

The determination module 153 determines whether or not the jam of the medium has occurred, based on the sound signal received from the sound A/D converter. The determination module 153 determines that a large sound is generated due to a distortion, etc., of the medium, and determines that the jam of the medium has occurred when a state in which a signal value of the sound signal is equal to or more than a predetermined value continues for a predetermined time or more. The predetermined value and the predetermined time are predetermined by a prior experiment. When the determination module 153 determines that the jam of the medium has occurred due to sound, the determination module 153 determines that the conveyance abnormality of the medium has occurred.

Further, the determination module 153 may determine whether or not a multi-feed of the medium has occurred as the conveyance abnormality of the medium. In that case, the determination module 153 determines whether or not the multi-feed of the medium has occurred based on the ultrasonic signal received from the ultrasonic sensor 117. The determination module 153 determines that the multi-feed of the medium has occurred when a signal value of the ultrasonic signal is less than a predetermined value, and the determination module 153 determines that the multi-feed of the medium has not occurred when the signal value of the ultrasonic signal is equal to or more than the predetermined value.

FIG. 8 is a flowchart illustrating an operation example of the notification processing. The flow of operation shown in FIG. 8 is performed in step S112 of the flow chart shown in FIG. 5.

First, the notification module 154 determines whether or not the conveyance abnormality occurred presently is the first conveyance abnormality occurred after the start of use (after shipping) of the medium conveying apparatus 100 (step S201). When the conveyance abnormality occurred presently is the first conveyance abnormality, the notification module 154 resets (initializes to 0) a counter value for determining a type of the instruction to notify the user (step S202). Next, the notification module 154 sets the normal flag to OFF (step S203), and ends the series of steps. In this case, the notification module 154 does not notify the cleaning instruction and the replacement instruction of the feed roller 113 to the user.

On the other hand, when the conveyance abnormality occurred presently is not the first conveyance abnormality, the notification module 154 calculates the occurrence degree of the conveyance abnormality in a plurality of media fed by the feed roller 113 (step S204). The notification module 154, for example, calculates the number of media fed from when the conveyance abnormality last occurred to when the conveyance abnormality newly occurred, as the occurrence degree of the conveyance abnormality. The notification module 154 reads the medium ID of the medium in which the conveyance abnormality last occurred from the storage device 140, and compares it with the medium ID assigned to the medium currently fed, to calculate the number of the medium that has been fed from when the conveyance abnormality last occurred to when the conveyance abnormality newly occurred.

Next, the notification module 154 determines whether or not the number of media calculated as the occurrence degree of the conveyance abnormality is equal to or less than a medium number threshold (step S205). The medium number threshold is an example of a first predetermined value and a second predetermined value. The medium number threshold is set to, for example, half (e.g., 250) of the maximum number of media placed on the medium tray 103 collectively at a time and conveyed. Thus, the notification module 154 can notify the user of the cleaning instruction of the feed roller 113 in a process to be described later, when the conveyance abnormality occurs twice in a group of media conveyed collectively. The medium number threshold may be set to, for example, an average value, a maximum value or a minimum value of the number of media calculated as the occurrence degree of the conveyance abnormality in a prior experiment in which the medium is fed using the feed roller 113 to which a large amount of paper dust is adhered.

When the number of media calculated as the occurrence degree of the conveyance abnormality is more than the medium number threshold, the notification module 154 resets the counter value (step S202), sets the normal flag to OFF (step S203), and ends the series of steps. In this case, the notification module 154 considers that the feed roller 113 does not need to be cleaned or exchange yet, and does not notify the user of the cleaning instruction and the replacement instruction of the feed roller 113 since an occurrence frequency of the conveyance abnormality is low.

On the other hand, when the number of media calculated as the occurrence degree of the conveyance abnormality is equal to or less than the medium number threshold, the notification module 154 determines whether or not the normal flag is set to OFF (step S206). When the normal flag is set to ON, the notification module 154 resets the counter value (step S202), sets the normal flag to OFF (step S203), and ends the series of steps. In this case, the notification module 154 considers that the feed roller 113 does not need to be cleaned or exchange yet, and does not notify the user of the cleaning instruction and the replacement instruction of the feed roller 113 since the feed roller 113 is normal,

On the other hand, when the normal flag is set to OFF, the notification module 154 increments the counter value (+1) (step S207).

Next, the notification module 154 determines whether or not the counter value is 1 (step S208). When the counter value is 1, the notification module 154 notifies of the user the cleaning instruction of the feed roller 113 (step S209). The notification module 154 notifies the user of the cleaning instruction of the feed roller 113 by displaying it to the display device 106 or by transmitting it to the information processing apparatus via the interface device 132. Next, the notification module 154 sets the normal flag to OFF (step S203), and ends the series of steps.

On the other hand, when the counter value is not 1, i.e., the counter value is 2 or more, the notification module 154 determines whether or not the total number of media fed by the medium conveying apparatus 100 from the start of use (shipment) to the present is equal to or more than a total number threshold (step S210). The notification module 154 specifies the medium ID assigned to the medium currently fed as the total number of media fed by the medium conveying apparatus 100, and compares it with the total number threshold. The total number threshold is set in consideration of the component life of the feed roller 113, and is set to, for example, 600,000, etc.

When the total number of media fed by the medium conveying apparatus 100 is less than the total number threshold, the notification module 154 sets the normal flag to OFF (step S203), and ends the series of steps. In this case, the notification module 154 considers that the feed roller 113 does not need to be replaced yet, and does not notify the user of the replacement instruction of the feed roller 113.

On the other hand, when the total number of media fed by the medium conveying apparatus 100 so far is equal to or more than the total number threshold, the notification module 154 notifies the user of the replacement instruction of the feed roller 113 (step S211). The notification module 154 notifies the user of the replacement instruction of the feed roller 113 by displaying it the display device 106 or by transmitting it to the information processing apparatus via the interface device 132. Next, the notification module 154 sets the normal flag to OFF (step S203), and ends the series of steps.

Thus, the notification module 154 notifies the user of the cleaning instruction or the replacement instruction of the feed roller 113 based on the occurrence degree of the conveyance abnormality for a plurality of media fed by the feed roller 113. The notification module 154 notifies the user of the cleaning instruction or the replacement instruction of the feed roller 113 when the conveyance abnormality of the medium occurs frequently, and does not notify the user of each instruction when the conveyance abnormality of the medium has occurred discretely. That is, the notification module 154 notifies the user of the cleaning instruction or the replacement instruction of the feed roller 113 only when the conveyance abnormality of the medium is likely to occur due to the feed roller 113, such as when the feed roller 113 is dirty or worn away. Since the user does not need to clean or replace the feed roller 113 when the conveyance abnormality of the medium does not occur due to the feed roller 113, the medium conveying apparatus 100 can reduce the labor of the user. Further, since the possibility that the feed roller 113 is replaced is reduced when the conveyance abnormality of the medium does not occur due to the feed roller 113, the medium conveying apparatus 100 can suppress the consumption of replacement parts.

In particular, the notification module 154 calculates the number of media fed from when the conveyance abnormality last occurred to when the conveyance abnormality newly occurred as the occurrence degree of the conveyance abnormality. Thus, the medium conveying apparatus 100 can calculate the occurrence degree of the conveyance abnormality of the medium at a low load, and can reduce the processing load and the processing time of the medium read processing.

Further, the notification module 154 notifies the user of the cleaning instruction of the feed roller 113 when the number of media fed from when the conveyance abnormality last occurred to when the conveyance abnormality newly occurred is equal to or less than the medium number threshold. Further, the notification module 154 notifies the user of the replacement instruction of the feed roller 113 when the number of media fed from when the cleaning instruction was notified to the user to when the conveyance abnormality newly occurred is equal to or less than the medium number threshold. Thus, the notification module 154 can notify the user of the cleaning instruction and replacement instruction in stages, and thereby, the user can perform the cleaning and the replacement of the feed roller 113 in stages. Since the cleaning is performed before the replacement of the feed roller 113, the frequency at which the feed roller 113 is replaced is reduced, and thereby, the medium conveying apparatus 100 can suppress the consumption of replacement parts.

Further, in step S206, the notification module 154 notifies the user of the cleaning instruction or the replacement instruction of the feed roller 113 when the normal flag is OFF. That is, the notification module 154 notifies the user of the cleaning instruction or the replacement instruction of the feed roller 113 based on the slip rate between the feed roller 113 and the medium fed by the feed roller 113. Thus, the notification module 154 can more accurately determine whether or not the feed roller 113 is dirty, or whether or not the feed roller 113 is worn away.

In particular, the notification module 154 notifies the user of the cleaning instruction or the replacement instruction of the feed roller 113 based on the moving average value of the slip rate. Thus, the notification module 154 can even more accurately determine whether or not the feed roller 113 is dirty, or whether or not the feed roller 113 is worn away.

Further, the notification module 154 does not notify the user of the cleaning instruction or the replacement instruction of the feed roller 113 when the normal flag is ON, i.e., when the moving average value calculated by the calculation module 152 from when the conveyance abnormality occurred last time to when the conveyance abnormality occurred this time, is equal to or less than a threshold value the slip threshold. Thus, the notification module 154 does not notify the user of the cleaning instruction or the replacement instruction of the feed roller 113 when there is a high possibility that the conveyance abnormality is not caused by the feed roller 113 even when the conveyance abnormality of the medium has occurred. Therefore, the medium conveying apparatus 100 can suppress the notification of the erroneous instruction to the user, and thereby, suppress that the user feels troublesome.

In step S204, the notification module 154 may calculate the occurrence rate of the conveyance abnormality with respect to the number of the fed media as the occurrence degree of the conveyance abnormality of the media. In that case, the notification module 154 calculates the occurrence rate of the conveyance abnormality for the most recent predetermined number of media. The notification module 154 may calculate the occurrence rate for the medium fed after the start of use (after shipment) of the medium conveying apparatus 100, or after the feed roller 113 is replaced previously.

In that case, in step S205, the notification module 154 determines whether or not the occurrence rate calculated as the occurrence degree of the conveyance abnormality is equal to or less than an occurrence rate threshold. The occurrence rate threshold is set to, for example, an average value, a maximum value or a minimum value of the occurrence rate calculated as the occurrence degree of the conveyance abnormality in a prior experiment in which the medium is fed using the feed roller 113 to which a large amount of paper dust is adhered. When the occurrence rate is equal to or less than the occurrence rate threshold, the notification module 154 shifts the process to step S202, and does not notify the user of the cleaning instruction and the replacement instruction of the feed roller 113. On the other hand, when the occurrence rate is more than the occurrence rate threshold, the notification module 154 moves the process to step S206, and notifies the user of the cleaning instruction or the replacement instruction of the feed roller 113. Thus, the notification module 154 can appropriately notify the user of the cleaning instruction or the replacement instruction of the feed roller 113.

Further, in step S205, the notification module 154 may use different thresholds to each other, as the medium number threshold used when the counter value is 0, and the medium number threshold used when the counter value is 1 or more. That is, the notification module 154 may use different thresholds to each other, as the medium number threshold used when notifying the cleaning instruction, and the medium number threshold used when notifying the replacement instruction.

For example, the notification module 154 uses, as the medium number threshold used when notifying the cleaning instruction, a threshold having a value less than the medium number threshold used when notifying the replacement instruction. Thus, the notification module 154 can notify the cleaning instruction frequently, and thereby, can reduce the amount of paper dust adhering to the surface of the feed roller 113. Alternatively, the notification module 154 may use, as the medium number threshold used when notifying the replacement instruction, a threshold having a value less than the medium number threshold used when notifying the cleaning instruction. Thus, the notification module 154 can notify the replacement instruction at an early stage when the conveyance abnormality of the medium occurs even though the feed roller 113 is cleaned up, and thereby, can reduce the occurrence of the conveyance abnormality of the medium.

Further, the process of step S206 may be omitted, and the notification module 154 may notify the user of the cleaning instruction or the replacement instruction of the feed roller 113 without using the slip rate. Further, the processes of steps S207 to S208 may be omitted, and the notification module 154 may fixedly notify the user of any one of the cleaning instruction or the replacement instruction of the feed roller 113, regardless of the counter value. Further, the process of step S210 may be omitted, and the notification module 154 may notify the user of the replacement instruction of the feed roller 113, regardless of the total number of media fed by the medium conveying apparatus 100 so far.

FIG. 9 is a graph for illustrating a relationship between cleaning of the feed roller 113 and the slip of the medium.

The horizontal axis of the graph 900 of FIG. 9 shows the number of media fed by the medium conveying apparatus 100, the vertical axis of the graph 900 shows the moving average value of the slip rate. A solid line 901 indicates the moving average value of the slip rate when the feed roller 113 is not cleaned up, and a dotted line 902 indicates the moving average value of the slip rate when the feed roller 113 is cleaned up. When the feed roller 113 is not cleaned up, paper dust, etc., adhering to the fed paper adheres to the feed roller 113. As shown in a solid line 901, as the number of the fed media increases, the amount of paper dust adhering to the feed roller 113 increases. Therefore, the slip occurs easily between the feed roller 113 and the medium, and the conveyance abnormality of the medium occurs easily. On the other hand, when the feed roller 113 is cleaned up, the paper dust adhering to the feed roller 113 is removed. Therefore, as shown in the dotted line 902, the occurrence of the slip between the feed roller 113 and the medium is suppressed, and the occurrence of the conveyance abnormality of the medium is suppressed.

However, when the number of the fed media increases to some extent, the feed roller 113 is worn away, and the grooves formed on the surface of the feed roller 113 are worn down. Therefore, as shown in the dotted line 902, when the number of the fed media increases to some extent, the moving average value of the slip rate increases exponentially, even though the feed roller 113 is cleaned up, and the slip occurs easily between the feed roller 113 and the medium.

The medium conveying apparatus 100 notifies the user of the cleaning instruction of the feed roller 113 before notifying the user of the replacement instruction of the feed roller 113. Thus, the medium conveying apparatus 100 prevents the feed roller 113 from being replaced due to the conveyance abnormality of the medium caused by the paper dust adhering to the feed roller 113 rather than the wear of the feed roller 113, and thereby, can suppress the consumption of replacement parts.

Further, the medium conveying apparatus 100 sets a value less than the number of media at which the moving average value of the slip rate exponentially increases, as the total number threshold, and the medium conveying apparatus 100 does not notify the user of the replacement instruction of the feed roller 113 when the total number of media fed by the medium conveying apparatus 100 is less than the total number threshold. Thus, the medium conveying apparatus 100 suppresses the feed roller 113 from being replaced due to the conveyance abnormality of the medium caused by other factors rather than the wear of the feed roller 113, and thereby, can suppress the consumption of replacement parts.

Further, the medium conveying apparatus 100 sets the slip threshold between the moving average value of the slip rate when the feed roller 113 is not cleaned up and the moving average value of the slip rate when the feed roller 113 is cleaned up at the time when the total number of the fed media is the total number threshold. When the moving average value of the slip rate is equal to or less than the slip threshold, the medium conveying apparatus 100 does not notify the user of the cleaning instruction and the replacement instruction of the feed roller 113. Thus, the medium conveying apparatus 100 can suppress notifying the user of each instruction even though the feed roller 113 is cleaned up, and thereby, make suppress excessive cleaning or replacement of the feed roller 113.

FIG. 10 is a graph illustrating an example of a transition of the moving average value of the slip rate.

The horizontal axis of the graph 1000 of FIG. 10 shows the number of media fed by the medium conveying apparatus 100, the vertical axis of the graph 1000 indicates the moving average value of the slip rate. In the example shown in FIG. 10, the conveyance abnormality has occurred for each of the N1-th to N7-th fed media. Since the media fed between the N1-th fed medium and the N2-th fed medium include the medium whose moving average value is equal to or less than the slip threshold, the normal flag is set to ON in step S107 of FIG. 5. Therefore, when the conveyance abnormality occurs for the N2-th fed medium, it is determined that the normal flag is set to ON in step S206 of FIG. 8, and the cleaning instruction of the feed roller 113 is not notified.

Also, the number of media fed between the N2-th fed medium and the N3-th fed medium is more than the medium number threshold. Therefore, when the conveyance abnormality occurs for the N3-th fed medium, it is determined that the medium number is more than the medium number threshold in step S205 of FIG. 8, the counter value is reset, and the cleaning instruction of the feed roller 113 is not notified.

On the other hand, the media fed between the N3-th fed medium and the N4-th fed medium do not include the medium whose moving average value is equal to or less than the slip threshold, and the number of media fed between the N3-th fed medium and the N4-th fed medium is equal to or less than the medium number threshold. Therefore, when the conveyance abnormality occurs for the N4-th fed medium, the counter value is set to 1 in step S207 of FIG. 8, and the cleaning instruction of the feed roller 113 is notified. Thus, the moving average value of the slip rate is reduced for the medium fed thereafter.

Also, the number of media fed between the N4-th fed medium and the N5-th fed medium is more than the medium number threshold. Therefore, when the conveyance abnormality occurs for the N5-th fed medium, it is determined that the medium number is more than the medium number threshold in step S205 of FIG. 8, the counter value is reset, and the replacement instruction of the feed roller 113 is not notified.

On the other hand, the media fed between the N5-th fed medium and the N6-th fed medium do not include the medium whose moving average value is equal to or less than the slip threshold, and the number of media fed between the N5-th fed medium and the N6-th fed medium is equal to or less than the medium number threshold. Therefore, when the conveyance abnormality occurs for the N6-th fed medium, the counter value is set to 1 in step S207 of FIG. 8, and the cleaning instruction of the feed roller 113 is notified. Thus, the moving average value of the slip rate is reduced for the medium fed thereafter.

Also, the media fed between the N6-th fed medium and the N7-th fed medium do not include the medium whose moving average value is equal to or less than the slip threshold, and the number of media fed between the N6-th fed medium and the N7-th fed medium is equal to or less than the medium number threshold. Therefore, when the conveyance abnormality occurs for the N7-th fed medium, the counter value is set to 2 in step S207 of FIG. 8, and the replacement instruction of the feed roller 113 is notified.

Thus, the medium conveying apparatus 100 does not notify the user of a warning when the occurrence frequency of the conveyance abnormality is low, or when the moving average value of the slip rate is small, even when the conveyance abnormality of the medium occurs. Thus, the medium conveying apparatus 100 can suppress excessive cleaning or replacement of the feed roller 113.

In particular, when the medium conveying apparatus 100 is a scanner, the fed medium includes various types of paper, such as art paper, coated paper, matte coated paper, fine paper, medium paper, etc. Also, the medium conveying apparatus 100 feeds and conveys the medium at various settings (conveyance speed) depending on the user's purpose. The occurrence degree of conveyance abnormality of the medium varies depending on the type of paper and the setting of the apparatus. The medium conveying apparatus 100 statistically determines whether or not the feed roller 113 is normal based on the occurrence degree of the conveyance abnormality of the medium and/or the moving average value of the slip rate, and thereby, can accurately determine whether or not the feed roller 113 is normal.

As described in detail above, the medium conveying apparatus 100 notifies the user of the cleaning instruction or the replacement instruction of the feed roller 113 based on the occurrence degree of the conveyance abnormality of the medium. Thus, the medium conveying apparatus 100 can notify the user of the cleaning instruction or the replacement instruction of the feed roller 113 at an appropriate timing.

Further, the medium conveying apparatus 100 can suppress the occurrence of the conveyance abnormality of the medium, while suppressing excessive cleaning or replacement of the feed roller 113. Thus, the medium conveying apparatus 100 can reduce time and effort for the user to reset and re-feed the medium, and suppress the occurrence of the damage to the medium.

The medium conveying apparatus 100 may also determine that the pick roller 112 and/or the brake roller 114 are dirty or worn away as with the feed roller 113, when notifying the cleaning instruction or the replacement instruction of the feed roller 113. In that case, the medium conveying apparatus 100 may notify the cleaning instruction or the replacement instruction of the pick roller 112 and/or the brake roller 114 together with the cleaning instruction or the replacement instruction of the feed roller 113.

FIG. 11 is a diagram for illustrating a conveyance path inside a medium conveying apparatus 200 according to another embodiment.

As shown in FIG. 11, the medium conveying apparatus 200 includes the respective portions of the medium conveying apparatus 100. However, the medium conveying apparatus 200 does not include an encoder 115, and instead, includes a third medium sensor 221.

The third medium sensor 221 is located on the downstream side of the second medium sensor 116 and on the upstream side of the first conveying roller 118 a and the first driven roller 119 a in the medium conveying direction A2. The second medium sensor 116 and the third medium sensor 221 is an example of two sensors spaced apart in the medium conveying direction A2. The third medium sensor 221 includes a light emitter and a light receiver provided on one side with respect to the conveyance path of the medium, and a reflection member such as a mirror provided at a position facing the light emitter and the light receiver with the conveyance path in between. The light emitter is an LED, etc., and emits light toward the medium conveyance path. On the other hand, the light receiver receives light projected by the light emitter and reflected by the reflection member, and generates and outputs a third medium signal being an electric signal based on intensity of the received light.

When a medium exists at a position of the third medium sensor 221, light projected by the light emitter is shaded by the medium. Therefore, a signal value of the third medium signal is changed in a state in which the medium exists at the position of the third medium sensor 221 and a state in which a medium does not exist at the position. Thus, the third medium sensor 221 detects whether or not the medium exists at the position, to detect the fed medium. The light emitter and the light receiver of the third medium sensor 221 may be provided at positions facing one another with the conveyance path in between, and the reflection member may be omitted. The third medium sensor 221 may detect the presence of the medium by a contact detection sensor, etc., in which a predetermined current flows when a medium is in contact or a medium is not in contact.

In the medium conveying apparatus 200, the calculation module 152 calculates the slip rate based on the drive amount of the motor 131 and the time for which the medium fed by the feed roller 113 passes between the second medium sensor 116 and the third medium sensor 221. That is, in step S104 of FIG. 5, the calculation module 152 periodically acquires the second medium signal and the third medium signal from the second medium sensor 116 and the third medium sensor 221, respectively. The calculation module 152, in the same manner as in the process of step S108, detects the timing at which the front end of the medium passes through the position of the second medium sensor 116 and the third medium sensor 221, based on the second medium signal and the third medium signal.

The calculation module 152 specifies the drive amount (the number of pulses) by which the control module 151 drives the motor 131 during the period from when the front end of the medium passes through the position of the second medium sensor 116 to when it passes through the position of the third medium sensor 221. The calculation module 152 calculates the movement distance of the outer peripheral surface of the feed roller 113, by multiplying the specified drive amount (the number of pulses) and the movement distance of the outer peripheral surface of the feed roller 113 per pulse. The calculation module 152 calculates the distance between the second medium sensor 116 and the third medium sensor 221 as the movement distance of the fed medium. The calculation module 152 calculates the slip rate according to the following equation (2) based on the movement distance of the outer peripheral surface of the feed roller 113 and the movement distance of the fed medium.

(the slip rate)=1−(the movement distance of the fed medium)/(the movement distance of the outer peripheral surface of the feed roller 113)  (2)

As described in detail above, the medium conveying apparatus 200 can accurately calculate the slip rate of the medium, even when using the drive amount of the motor 131 and the time for which the medium passes between the second medium sensor 116 and the third medium sensor 221. Therefore, the medium conveying apparatus 200 can notify the user of the cleaning instruction or the replacement instruction of the feed roller 113 at an appropriate timing.

FIG. 12 is a diagram illustrating a schematic configuration of a processing circuit 350 of a medium conveying apparatus according to another embodiment.

The processing circuit 350 is used in place of the processing circuit 150 of the medium conveying apparatus 100 or 200 and executes a medium reading processing, etc., instead of the processing circuit 150. The processing circuit 350 includes a control circuit 351, a calculation circuit 352, a determination circuit 353 and a notification circuit 354, etc. Note that each unit may be configured by an independent integrated circuit, a microprocessor, firmware, etc.

The control circuit 351 is an example of a control module, and has a function similar to the control module 151. The control circuit 351 receives the operation signal from the operation device 105, the first medium signal from the first medium sensor 111, and the second medium signal from the second medium sensor 116. The control circuit 351 controls the motor 131 to control each roller based on the received information. Further, the control circuit 351 acquires the input image from the imaging device 120, and outputs it to the interface device 132.

The calculation circuit 352 is an example of a calculation module, and has a function similar to the calculation module 152. The calculation circuit 352 receives the distance signal from the encoder 115 or receives the second medium signal and the third medium signal from the second medium sensor 116 and the third medium sensor 221. The calculation circuit 352 calculates the slip rate and the moving average value of the slip rate of the medium based on the received signal, and outputs the calculation result to the notification circuit 354.

The determination circuit 353 is an example of a determination module, and has a functions similar to the determination module 153. The determination circuit 353 receives the second medium signal from the second medium sensor 116 or receives the ultrasonic signal from the ultrasonic sensor 117. The calculation circuit 353 determines whether or not the conveyance abnormality of the medium has occurred based on the received signal, and outputs the determination result to the notification circuit 354.

The notification circuit 354 is an example of a notification module, and has a functions similar to the notification module 154. The notification circuit 354 receives the calculation result of the moving average value from the calculation circuit 352 and the determination result of the conveyance abnormality of the medium from the determination circuit 353. The notification circuit 354 notifies the user of the cleaning instruction or the replacement instruction of the feed roller 113 by displaying it to the display device 106 or by transmitting it to the information processing apparatus via the interface device 132, based on the received information.

As described in detail above, the medium conveying apparatus can notify the user of the cleaning instruction or the replacement instruction of the feed roller 113 at an appropriate timing, even when the medium reading process is performed by the processing circuit 350.

According to some embodiments, the medium conveying apparatus, the method and the computer-readable, non-transitory medium storing the computer program can notify the user of the cleaning instruction or the replacement instruction of the feed roller at an appropriate timing.

All examples and conditional language recited herein are intended for pedagogical purposes to aid the reader in understanding the invention and the concepts contributed by the inventor to furthering the art, and are to be construed as being without limitation to such specifically recited examples and conditions, nor does the organization of such examples in the specification relate to a showing of the superiority and inferiority of the invention. Although the embodiment(s) of the present inventions have been described in detail, it should be understood that the various changes, substitutions, and alterations could be made hereto without departing from the spirit and scope of the invention. 

What is claimed is:
 1. A medium conveying apparatus comprising: a storage device; a feed roller to feed a medium; and a processor to determine whether a conveyance abnormality of the medium fed by the feed roller has occurred, store in the storage device that the conveyance abnormality has occurred and stop feeding of the medium when the processor determines that the conveyance abnormality has occurred, and notify a user of a cleaning instruction or a replacement instruction of the feed roller based on an occurrence degree of the conveyance abnormality for a plurality of media fed by the feed roller.
 2. The medium conveying apparatus according to claim 1, wherein the occurrence degree of the conveyance abnormality is the number of media fed from when the conveyance abnormality last occurred to when the conveyance abnormality newly occurred, or an occurrence rate of the conveyance abnormality with respect to the number of fed media.
 3. The medium conveying apparatus according to claim 1, wherein the processor notifies the user of the cleaning instruction of the feed roller when the number of the media fed from when the conveyance abnormality last occurred to when the conveyance abnormality newly occurred is equal to or less than a first predetermined value, and notifies the user of the replacement instruction of the feed roller when the number of media fed from when the cleaning instruction was notified to when the conveyance abnormality newly occurred is equal to or less than a second predetermined value.
 4. The medium conveying apparatus according to claim 1, wherein the processor calculates a slip rate between the feed roller and the medium fed by the feed roller, and notifies the user of the cleaning instruction or the replacement instruction of the feed roller further based on the slip rate.
 5. The medium conveying apparatus according to claim 4, wherein the processor calculates a moving average value of the slip rate in a predetermined number of media fed by the feed roller, and notifies the user of the cleaning instruction or the replacement instruction of the feed roller based on the moving average value.
 6. The medium conveying apparatus according to claim 5, wherein the processor does not notify the user of the cleaning instruction or the replacement instruction of the feed roller when the moving average value calculated from when the conveyance abnormality occurred last time to when the conveyance abnormality occurred this time, is equal to or less than a threshold.
 7. The medium conveying apparatus according to claim 4, further comprising: a motor to drive the feed roller; and a sensor to detect a movement distance of the medium fed by the feed roller, wherein the processor calculates the slip rate based on a drive amount of the motor and the movement distance.
 8. The medium conveying apparatus according to claim 4, further comprising: a motor to drive the feed roller; and two sensors spaced apart in a medium conveying direction, wherein the processor calculates the slip rate based on a drive amount of the motor and time for which the medium fed by the feed roller passes between the two sensors.
 9. A method for notifying a user, comprising: feeding a medium, by a feed roller; determining whether a conveyance abnormality of the medium fed by the feed roller has occurred; storing in a storage device that the conveyance abnormality has occurred and stopping feeding of the medium when it is determined that the conveyance abnormality has occurred; and notifying a user of a cleaning instruction or a replacement instruction of the feed roller based on an occurrence degree of the conveyance abnormality for a plurality of media fed by the feed roller.
 10. The method according to claim 9, wherein the occurrence degree of the conveyance abnormality is the number of media fed from when the conveyance abnormality last occurred to when the conveyance abnormality newly occurred, or an occurrence rate of the conveyance abnormality with respect to the number of fed media.
 11. The method according to claim 9, wherein the cleaning instruction of the feed roller is notified to the user when the number of the media fed from when the conveyance abnormality last occurred to when the conveyance abnormality newly occurred is equal to or less than a first predetermined value, and the replacement instruction of the feed roller is notified to the user when the number of media fed from when the cleaning instruction was notified to when the conveyance abnormality newly occurred is equal to or less than a second predetermined value.
 12. The method according to claim 9, wherein a slip rate between the feed roller and the medium fed by the feed roller is calculated, and wherein the cleaning instruction or the replacement instruction of the feed roller are notified to the user further based on the slip rate.
 13. The method according to claim 12, wherein a moving average value of the slip rate in a predetermined number of media fed by the feed roller is calculated, and wherein the cleaning instruction or the replacement instruction of the feed roller is notified to the user based on the moving average value.
 14. The method according to claim 13, wherein the cleaning instruction or the replacement instruction of the feed roller are not notified to the user when the moving average value calculated from when the conveyance abnormality occurred last time to when the conveyance abnormality occurred this time, is equal to or less than a threshold.
 15. A computer-readable, non-transitory medium storing a computer program, wherein the computer program causes a medium conveying apparatus including a storage device, and a feed roller to feed a medium, to execute a process, the process comprising: determining whether a conveyance abnormality of the medium fed by the feed roller has occurred; storing in the storage device that the conveyance abnormality has occurred and stopping feeding of the medium when it is determined that the conveyance abnormality has occurred; and notifying a user of a cleaning instruction or a replacement instruction of the feed roller based on an occurrence degree of the conveyance abnormality for a plurality of media fed by the feed roller.
 16. The computer-readable, non-transitory medium according to claim 15, wherein the occurrence degree of the conveyance abnormality is the number of media fed from when the conveyance abnormality last occurred to when the conveyance abnormality newly occurred, or an occurrence rate of the conveyance abnormality with respect to the number of fed media.
 17. The computer-readable, non-transitory medium according to claim 15, wherein the cleaning instruction of the feed roller is notified to the user when the number of the media fed from when the conveyance abnormality last occurred to when the conveyance abnormality newly occurred is equal to or less than a first predetermined value, and the replacement instruction of the feed roller is notified to the user when the number of media fed from when the cleaning instruction was notified to when the conveyance abnormality newly occurred is equal to or less than a second predetermined value.
 18. The computer-readable, non-transitory medium according to claim 15, wherein a slip rate between the feed roller and the medium fed by the feed roller is calculated, and wherein the cleaning instruction or the replacement instruction of the feed roller are notified to the user further based on the slip rate.
 19. The computer-readable, non-transitory medium according to claim 18, wherein a moving average value of the slip rate in a predetermined number of media fed by the feed roller is calculated, and wherein the cleaning instruction or the replacement instruction of the feed roller is notified to the user based on the moving average value.
 20. The computer-readable, non-transitory medium according to claim 19, wherein the cleaning instruction or the replacement instruction of the feed roller are not notified to the user when the moving average value calculated from when the conveyance abnormality occurred last time to when the conveyance abnormality occurred this time, is equal to or less than a threshold. 